HTMLFormElement.requestSubmit(submitter) accepted any element and submitted
silently. Per the HTML spec (and Chrome) it must throw a TypeError when the
submitter is not a submit button, and a NotFoundError DOMException when the
submitter is not owned by the form; both checks run before the submit event.
Adds an _isSubmitButton predicate (a <button> whose type is submit — the
default, including a missing/invalid type — or an <input> of type submit/image)
and validates the argument at the top of requestSubmit. submit() is untouched:
it correctly bypasses the event (#395).
Element.click() now gates on the same predicate rather than its own looser
check, so an internal click can never hand requestSubmit a submitter it would
reject (e.g. <div type="submit">, which is not a submit button and no longer
submits — matching Chrome). That also aligns click() with the CDP click path in
input.rs, which already treats <input type=image> as a submit button. The
input.rs call sites are already guarded by equivalent conditions and pass no
submitter on the Enter-key path, so they are unaffected.
Constraint validation is deliberately out of scope: obscura has no validity
engine (checkValidity is a stub returning true), so wiring it here would be a
no-op. Noted in #424 as separate work.
Full obscura-cdp suite (72) green.
Andrey Mnatsakanov
ccfa5fb87b